[1] Examples: in 2014 the people of Zurich decided (66% voted yes) to extend tram line 8, in 2017 that extension was opened. And just this year a the tram line 2 was extended to reach further into the suburbs of Zurich, and further work is planed for the next few years. People of Zurich also voted on these extensions, and will continue to in the coming years.
Similar thing happened with the subway that was never built. The station and a few tunnels where already dug because of renovations but the people voted no on building a subway. That part of HB turned into the SZU Station.
The tram tunnels by the Tierspital where also meant for the subway from what I recall. When they converted those for the use with trams they had several issues like the tunnel being not heigh enough. You can see the tracks are very low and the electrical connection on top is almost completely compressed.
https://en.m.wikipedia.org/wiki/Weinberg_Tunnel
https://www.zvv.ch/zvv/de/ueber-uns/projekte/durchmesserlini...
Other points not mentioned:
Switzerland has - effectively - no domestic car industry, so there were never any special interest groups with economic clout pushing to get rid of public transportation ala the US.
Zurich is not amenable to cars, and never will be because of how it's laid out.
The highways outside of the city are also designed in a way that makes capacity expansion extremely expensive and unfeasible. The Swiss need a way to limit or stop automobile usage growth, and heavily pushing public transportation is an effective way to do this.
...of course key tunnels and bridges will have mines (in the old demolition sense) in place to deny the infrastructure to an opponent. Same as they've done their road passes.
*https://www.railplus.com.au/images/maps/switzerland_map.jpg
That empty space would get jammed before you could say "this is not Switzerland, Dorothy".
If you have a valid ticket on your name but not on you, they will issue the fine but you will get it reduced to USD ~10-25 if you show your pass at a station beuro.
They realized a long time ago that 100% valid tickets in impossible. Everyone can forget to buy the right ticket at some point in their life. We are humans not machines.
It's also common to hear someone come in at the front and ask the bus driver to only go one stop without a ticket. I always thought it was a local or regional thing. Then I heard the same in a Toronto streetcar, on the other side of the world. A very surreal moment, it made me smile.
I think it's able to work because the fines are seen as high (90, 130, 160 CHF for the 1st, 2nd and 3rd violations and at some point they can force you to buy an annual pass) and because not paying the fines isn't really a viable option in Switzerland (they'll go into a debt register which is checked for a variety of reasons, it's kinda like the replacement for a credit report).
At the state level in the US, a lot can be accomplished. I suggest spending a few days in Seattle, their bus system is similar to what this article describes.